Pad-type idlers are used to support conveyor belts. For example, U.S. Pat. No. 5,799,780 issued to Raymond on Sep. 1, 1998, discloses a pad-type idler, referred to therein as a wear bar, on which a conveyor belt slides over an upper surface of the wear bar. In the first embodiment of Raymond, a feed idler assembly is disclosed which includes a generally U-shaped frame having a base, a pair of legs positioned on opposite ends of the base and a pair of shorter intermediate supports positioned between the legs. A plurality of plates is attached between the ends of the legs opposite the base and between the ends of the intermediate supports. Wear bars are attached to the plates on the side thereof opposite the base of the U-shaped frame. A conveyor belt slides over the wear bars.
With use, the upper surfaces of the wear bars become worn by the friction of the conveyor running over top of them. Care must be taken to replace the wear bars before they become worn down to the plates and the conveyor belt is damaged as a result. The challenge, however, is to gage the amount of wear on the wear bars. There is no wear indicator disclosed in Raymond for indicating that it is time to replace the wear bar.
Canadian patent application number 2,327,646, filed Dec. 6, 2000, discloses a pad-type idler for conveyor belts wherein the pads include bores. The bores extend from the bottom surface of the pad through the pad in an axis perpendicular to the bottom surface. The bores, however, do not extend the entire width of the pad to the top surface of the pad such that, the bores in an unworn pad are not visible from the top surface. As the top surface of the pad is worn by the action of a belt sliding over it down to the bores, the bores are exposed and appear as circular openings in the top surface of the pad. The appearance of the circular openings indicate the need to replace the pad.
While the wear indicator of the '646 application is useful for indicating when a pad has been worn to the point of needing replacement, it does not provide any progressive indication of wear to indicate the degree of pad wear at any given time. Therefore, it would be desirable to have a pad wear indicator which overcomes the above disadvantages in the prior art.